U.S. Smelting Refining and Mining Company Midvale Smelter built in 1902 as a copper smelter. Lead smelter was completed in 1905. Copper smelting discontinued in 1908. Lead smelting continued until smelter ceased operation in June, 1958 and smelter dismantled. Photo by: Bill Shipler. Courtesy: C.C. Hilton, U.S. Smelting and Refining Co.